Bioenergetic Profiling of the Differentiating Human MDS Myeloid Lineage with Low and High Bone Marrow Blast Counts

Abstract

Myelodysplastic syndromes (MDS) encompass a very heterogeneous group of clonal hematopoietic stem cell differentiation disorders with malignant potential and an elusive pathobiology. Given the central role of metabolism in effective differentiation, we performed an untargeted metabolomic analysis of differentiating myeloid lineage cells from MDS bone marrow aspirates that exhibited <5% (G1) or ≥5% (G2) blasts, in order to delineate its role in MDS severity and malignant potential. Bone marrow aspirates were collected from 14 previously untreated MDS patients (G1, n = 10 and G2, n = 4) and age matched controls (n = 5). Following myeloid lineage cell isolation, untargeted mass spectrometry-based metabolomics analysis was performed. Data were processed and analyzed using Metabokit. Enrichment analysis was performed using Metaboanalyst v4 employing pathway-associated metabolite sets. We established a bioenergetic profile coordinated by the Warburg phenomenon in both groups, but with a massively different outcome that mainly depended upon its group mitochondrial function and redox state. G1 cells are overwhelmed by glycolytic intermediate accumulation due to failing mitochondria, while the functional electron transport chain and improved redox in G2 compensate for Warburg disruption. Both metabolomes reveal the production and abundance of epigenetic modifiers. G1 and G2 metabolomes differ and eventually determine the MDS clinical phenotype, as well as the potential for malignant transformation.

Three-Dimensional Cell Metabolomics Deciphers the Anti-Angiogenic Properties of the Radioprotectant Amifostine

“…Data processing and statistical analysis: For both LC-MS-based [29] and NMRbased [30,31] approaches, an untargeted analytical approach was employed, and, hence, univariate as well as multivariate statistical methods were applied coupled to both unsupervised and supervised methods. Multiple data comparisons were performed as follows to shed light on amifostine's 3D cell anti-angiogenesis metabolome: (a) antiangiogenesis profiling upon deferoxamine stimulation (amifostine_deferoxamine, n = 14 vs. sunitinib_deferoxamine, n = 14), (b) anti-angiogenesis profiling upon VEGF-A stimulation (amifostine_VEGF-A, n = 14 vs. sunitinib_VEGF-A, n = 14), (c) drug-specific anti-angiogenesis profiling (amifostine_deferoxamine_VEGF-A, n = 28 vs. sunitinib_ deferoxamine_VEGF-A, n = 28), and (d) pathway-specific anti-angiogenesis profiling (amifostine_sunitinib_deferoxamine, n = 28 vs. amifostine_sunitinib_ VEGF-A, n = 28).…”

Exploiting the Role of Hypoxia-Inducible Factor 1 and Pseudohypoxia in the Myelodysplastic Syndrome Pathophysiology

“…It is possible that segmentation of the nuclear membrane during the apoptotic process allows for the retained NIM-IDC to enter the nucleus ( Figure 2 lower middle panels). In accordance with this hypothesis, our team has already established the reliance of differentiating cells of high-risk MDS on reduced GSH for survival and redox balance [ 34 ]. NIM-IDC is known to be retained intracellularly through binding with GSH and thus causing its depletion [ 28 , 31 ].…”

“…In fact, the elongation of the organelles in these cells is considered to be a compensatory phenomenon ( Figure 4 C). Our team has proved that disturbed mitochondrial function in both low and high intra BM blast percentage MDS by means of an aberrant metabolome [ 34 ]. Results of the present study come to confirm our data with the benign MDS subtypes suffering marked degradation of their dysfunctional mitochondria, leading to pseudohypoxia and HIF-1 stabilization while as disease progresses, genetic or epigenetic pressure leads to compensatory changes in mitochondrial function, and kinetics that remain faulty cause HIF-1 stability but are also rescued from degradation.…”

From the (Epi)Genome to Metabolism and Vice Versa; Examples from Hematologic Malignancy

“…Moreover, MDS cells also displayed increased levels of 1C-derived SAM and 2-HG compared to control cells. Interestingly, respiratory capacity and redox homeostasis were proposed to determine the ability of cells to compensate for the ongoing metabolic stress, which eventually functions as a driving force for the selection of blasts with increased oncogenic potential and shapes the MDS clinical phenotype [31].…”

“…Another link between metabolism and epigenetic regulation is the use of NAD+ as a cofactor by the sirtuin class of histone deacetylases. The latter enzymes often function as NAD+/NADH sensors [95], which may also explain the marked upregulation of acetyl-lysine under conditions of altered NAD+/NADH ratio observed in hematologic malignancies such as MDS [31].…”